Self-propelled vehicles for telpher railways



Oct. 4, 1966 p, GOIRAND 3,276,394

SELF-PROPELLED VEHICLES FOR TELPHER RAILWAYS Filed April l9. 1965 I 5 Shets-Sheet 1 TNVENT OR PIERRE GOIRAND BY A4 ATTORNEY Oct. 4, 1966 P. GOIRAND 3,276,394

SELF-PROPELLED VEHICLES FOR TELPHER RAILWAYS Filed April l9. 1965 5 Sheets-Sheet 2 INVENTOR PIERRE GO/RAND BY ATTORNEY P. GOIRAND SELF-PROPELLED VEHICLES FOR TELPHER RAILWAYS Filed April 19. 1965 5 Sheets-Sheet 5 PIERRE GO/RAND BY 7/ i g t ATTORNEY United States Patent 3,276,394 SELF-PROPELLED VEHICLES FOR TELPHER RAILWAYS Pierre Goirand, Grenoble, France, assignor to Atelrers Neyret-Beylier & Piccard-Pictet, Grenoble, France, a corporation of France Filed Apr. 19, 1965, Ser. No. 449,241 Claims priority, application France, Feb. 1, 1965, 4,764 14 Claims. (Cl. 105-153) This invention relates to the self-propelled vehicles employed in telpher railways, and is more particularly concerned with the driving mechanism for such vehicles.

Vehicles of the indicated type are usually suspended from a cable by carrier rollers, at least some of which are driving rollers. Associated with these carrier rollers are pressure rollers which bear against the underside of the cable to establish the conditions of adhesion for the driving rollers on the cable. The problem of maintaining satisfactory conditions of adhesion for such driving rollers is a difficult one because of the widely varying conditions of operation encountered by such a railway, such as, changes of slope of the cable, variations in the load carried, passage of the cable over the bearing bushes of pylons, etc. The art has devised means designed to take into account certain variations in such conditions of operation, such as when the cable passes over a pylon bearing bush, so as to modify the conditions of adhesion of the rollers in such manner that disturbances in the satisfactory operation of the vehicle are avoided. However, the measures which have heretofore been devised by the art for such purposes do not completely and conveniently solve the various problems of adhesion encountered in the operations of such vehicles.

The primary purpose of the present invention is to provide improved means capable of completely and satisfactorily adjusting the adhesive of the driving rollers to take care of the varying conditions to which the vehicle will be subjected in its operations.

In accordance with the invention, there is combined a regulating device adapted to select, preferably automatically, a certain pressure level from a predetermined range of pressure-levels, with an accumulator of the oleo-pneumatic type for maintaining each selected pressure level. The regulating device and the accumulator are incorporated in a hydraulic installation which includes a hydraulic jack arranged to push a pressure-roller against the vehicle supporting cable. The range of pressure levels associated with the regulating device may be either continuous, or preferably discontinuous, that is to say, comprising a plurality of steps of pressure values. The accumulator is advantageously placed in the vicinity of the jack and permits each pressure level chosen by the regulating device to be maintained irrespective of the position of its associated pressure roller, that is, whether the latter is in contact with or separated from the cable, it being noted, for example, that the pressure-rollers are permitted to move away from the cable at those places where the cable passes over the bearing bushes of the supporting pylons.

Another object of the invention is to provide means for controlling the regulating device automatically in dependence on the slope of the cable, in order to obtain good conditions of adhesion of the rollers.

It will be understood that when the cable is inclined or sloping, the various pressure-rollers associated with the vehicle are located at different levels. For purposes of identification, the lower roller or rollers in a group thereof shall be hereinafter referred to as bottom pressurerollers and the upper rollers in such group shall be referred to as the upper pressure-rollers. Also when the cable is sloping, the load of the vehicle which is carried by the carrier rollers, generally all driving rollers, is not ice uniformly distributed over all these rollers. Usually in such a situation the top carrier rollers become overloaded With respect to the bottom carrier rollers which, other things being equal, become under-loaded.

In accordance with the invention, the means for automatically controlling the regulating device in dependence on the cable slope are arranged to compensate for the effects which the aforesaid non-uniform distribution of the load may have, with the view of either preventing the pressure of the upper pressure-rollers from building up to an excessive value that would increase the wear of the upper driving and carrying rollers, or ensuring that the pressure of the bottom pressure-rollers has sufficient value to prevent the carrying and driving bottom rollers slippinl or, preferably, to accomplish these two conditions in combination. The invention provides with such control means a means for slope detection which is capable of distinguishing the bottom pressure-rollers from the upper pressure-rollers, and the said regulating device is controlled by such detection means so as to give more pressure to the bottom pressure-rollers than to the top pres sure-rollers.

A further object of the invention is to provide a slope measuring means capable of controlling the regulating device for at least one pressure-roller in such manner as to apply to the pressure-roller a different pressure, depend ing on whether the slope becomes greater or smaller, and more particularly to have the regulating device apply to the bottom pressure-rollers a pressure which increases over that being applied to the upper pressure-rollers as the slope becomes greater.

According to one form of construction embodying the invention, the pressure applied to the bottom pressurerollers is varied in dependence on the slope, while the pressure on the upper pressure-rollers remains constant. In an alternative form, the pressure on the bottom pressure-rollers remains constant while the pressure on the upper pressure-rollers is varied in dependence on the slope. In a still further alternative form of construction, the pressures on the bottom pressure-rollers and on the upper pressureollers are both varied as a function of the slope.

Other objects of the invention, as well as its characteristic features and advantages will be brought out in the following description of constructions which are given by way of example; reference therein being made to the accompanying drawings, in which:

FIG. 1 is a diagrammatic view in side elevation of a self-propelled vehicle of a telpher railway embodying the features of the invention;

FIG. 2 is a diagram illustrating the manner in which the jacks for the pressure-rollers are controlled;

FIG. 3 is a view similar to that of FIG. 1, but showing an alternative form of the invention;

FIG. 4 is a partial view relating to yet another alternative form; and

FIG. 5 is a force diagram showing the moments involved in the construction of FIG. 1.

Reference will first be made to FIG. 1 of the drawings. in which the reference numeral 10 indicates: the cable of a telpher railway from which is suspended a self-propelled vehicle generally designated 11. The vehicle 11 comprises a number of carrier rollers 12, which, in the example shown, are all driving rollers and therefore serve both to suspend the vehicle and to move it both in the upward and downward direction, and on the fiat when so required. The rollers 12 are driven by a motor 20 located in the vehicle 11 through the differential mechanisms 19. To ensure adequate adhesion of the carrier driving rollers 12 on the cable 10, there are provided pressure-rollers 13 which are pushed into contact with the underside of the cable 10 at an appropriate pressure.

It will be noted that the vehicle 11 shown in FIG. 1

of the drawings is provided with four groups of carrier rollers 12 and pressure rollers 13, and that each group thereof is composed of four carrier rollers 12 and two pressure rollers 13 each located between a pair ofradjacent carrier rollers 12. The driving rollers 12 of two adjacent groups of rollers 12 and 13 are drivingly connected together by a dififerential mechanism 19 and such adjacent connected groups are mounted on two trolleys 33 pivotally connected intermediate their ends at 34 to the end arms 32 of a double arm frame 32. The frame 32 is in turn pivotally mounted intermediate its ends at 31 on a bracket 30 provided on the top of the vehicle 11. In a similar manner the other two adjacent groups of rollers 12 and 13 are connected together and mounted on a supporting bracket 30 on the top of the vehicle. Each pair of carrier rollers 12 in each group is connected by a depending support 33' to its associated trolley 33. The pressure roller 13 associated with each such pair of a carrier rollers 12 is mounted on a rocking lever 35 pivotally connected at 35 to its associated trolley 33. Each rocking lever 35 is connected to and actuated by the rod 36 of a hydraulic jack 14 which forms part of a hydraulic installation for two of the connected adjacent groups of rollers 12 land 13 and comprising a regulating device generally designated 15 and adapted to select a given level of pressure from a predetermined range of pressure levels, and an oleo-pneum'atic accumulator 16 -associated with each hydraulic jack 14 and which maintains each selected pressure level irrespective of the position of the associated pressure-roller 13 with respect to the cable 10. As previously indicated, the pressure-roller 13 is allowed to move away slightly from beneath the cable 10, particularly during the movement of the vehicle past a pylon 17, where the cable 10 is supported by a carrier-bush 18 (FIG. 1).

As can be seen from FIG. 1, when the cable 10 is sloping, the rollers 12 are arranged at different levels. For purposes of explanation, the term bottom roller will be applied to the roller in each associated pair thereof which is at the lower level, and the roller in such pair which is located at the higher level shall be known as the top roller. The group of rollers 12 and 13 associated with the left hand frame 32, as viewed in FIG. 1 of the drawings shall be referred to as the bottom group, while the group of rollers '12 and 13 associated with the right hand frame 32 in such figure shall be referred to as the top group. It will be understood that during operation of the vehicle 11, the load thereof is distributed to a greater extent on the top group of rollers than on the bottom group of rollers, this being the case whether the vehicle is moving upwards or downwards or is stationary. The manner in which such forces are distributed is illustrated in FIG. of the drawings, wherein the bottom group of rollers of the telpher vehicle 11 is represented by the letter A and the top group of rollers thereof is represented by the letter B. The center of gravity of the vehicle 11 is designated G, and for the' sake of explanation is considered to be in the center of the vehicle. It will be understood that if the wire from which the vehicle 11 is suspended, were horizontal the vertical line C [from the center of gravity G would be at equal distances d and d from the two suspension points of the gnoups of rollers A and B and that as aconsequence the weight of the vehicle would be equally distributed between these two suspension points. The distribution of the weight of the vehicle at the two suspension' points is indicated by the arrows D, D and in the case discussed would be of equal lengths.

When, however, the cable 10 is sloping, as illustrated in FIG. 1 of the drawings, the vertical line C of the center of gravity is displaced nearer to the top group of rollers B as shown in FIG. 5 of the drawings, i.e., the distance d is lessened land the distance d lengthened. As the slope of the cable 10 increases and as a consequence, the distanced lessens, the load is proportionally distributed to a greater extent on the top group of rollers B than on the bottom group of rollers A, as indicated by the differences in lengths of the arrows D, D in FIG. 5 of the drawings. In accordance with the invention, slope detection means generally designated 21 are associated with each of the two hydraulic installations and the regulating device 15 in such installation is controlled by such means 21 so as to apply more pressure to the bottom pressure rollers than to the top pressure-rollers, in order that the pressure of the bottom rollers may be adequate and that the pressure of the top rollers may not be excessive, and that the conditions of adhesion are optimum for all the driving carrier rollers. It is also contemplated by the invention to control each of the regulating devices 15 by slope-measuring means generally designated 22, and in such manner that the pressure transmitted to an associated roller 13 is different depending on whether the slope is more or less steep, and so as to obtain the optimum conditions of adhesion for the whole of the driving carrier rollers. These two aspects of the invention are preferably combined, as in the example illustrated in FIGS. 1 and 2 of the drawings, wherein the slopedetection means 21 also functions as the slope measuring means 22 and comprise a U-tube having a central portion 23 which extends along the bottom of the vehicle 11 so that it is disposed substantially arallel to the cable 10 and therefore follows the slope of the cable 10. The U-tube has an arm 28 located at one end of the vehicle and an arm 29 located at the other end of the vehicle. The U-tube is partially filled with a liquid whose two levels are designated N and N Provided on the arm 28 are two submersible bodies 24 and 25 arranged to cooperate with liquid level N and cooperative with level N are two submersible bodies 26 and 27 provided on arm 29, the operations of which shall be hereinafter more fully explained.

Reference will now be made more particularly to FIG. 2 of the drawings, in which is shown the control of two of the bottom pressure-rollers 13 in the bottom group of rollers 12 and 13 associated with the left hand frame 32 as viewed in FIG. 1 of the drawings. As is shown more clearly in FIG. 2, each of the jacks 14 is connected by a conduit 37 to the oil chamber 38 of its associated ole'o-pneumatic accumulator 16, the air-chamber of which is seen at 39. The two chambers 38 and 39 are separated by a diaphragm 40. Each accumulator 16 is located in close proximity to its associated jack 14 as it has been found desirable for the satisfactory operation of the apparatus that the conduit 37 connecting the two should be fairly short in order that the exchanges of oil between the joined jack 14 land accumulator 16 take place very rapidly without appreciable loss of pressure. As in the example of FIGS. 1 and 2, the vehicle is of considerable size and necessitates a large number of driving carrier rollers 12, an accumulator 16 is arranged in the vicinity of each of the jacks 14. In the case of a vehicle of small size, there need be provided only a single accumulator which may be placed in the interior of the vehicle.

The oil chambers 38 of the accumulators 16 are connected by a piping system 41 to a series of a certain number (five in the example shown) of pressure cont-acts 42, 43, 44, 45 and 46 which are connected to and control the electric contacts 47, 48, 49, 50 and 51 respectively. The piping system 41 beyond the series of pressure contacts 42-46 is branched at 52 into two conduits 53 and 54. The conduit 53 is provided with an electro-valve 55 operated by an electro-magnet 56, and is supplied from a source of fluid pressure comprising a pressure accumulator 57 and a pump 58 which is connected at its suction end to a tank 59. The conduit 54 is provided with an electr c-valve 6t) operated by an electro-magnet 61 and is also connected to the tank 59. The electro-valves 55 and 60 are closed when their electro-magnets 56 and 61 respectively are deenergized and open when the electromagnets 56 and 61 are energized.

The level N of liquid in the -arm 28 of the U-tube 23, which is rigidly fixed to the vehicle 11, follows the variations of inclination of the vehicle. The movements of this level cause the pivotal movement, from their top position to their bottom position or conversely, of two electric contactors 62 and 63. The contactor 62 cooperates with a bottom switch 64 and a top switch 65. The contactor 63 cooperates with a bottom switch 66 and a top switch 67. The means which control the pivotal movements of the contactors 62 and 63 are represented diagrammatically by the levers 68 and 69 and the aforesaid submersible bodies 24 and 25 which are in the nature of floats, the whole constituting the detection and slopemeasuring means 21, 22. The means 21, 22 may of course be constituted of any other suitable contact-operat ing members acting under the influence of the position of a liquid level.

One of the line terminals 72 connecting the control circuit to a suitable source of electric current is connected directly to one of the terminals of the electr c-magnets 56 and 61, the other terminals of the latter being connectible to the other line terminal 73 when electric current passes through one or more of the switches 47, 48, 4-9, 50, 51, 64, 65, 66 and 67 in the manner shown in FIG. 2.

The pressure contact-s 42, 43, 44, 45 and 46 of the regulating device 15 are devices which open or close an electric contact (the contacts 47, 48, 49, 50 and 51 respectively) depending on whether the oil pressure in the con duit 41 reaches a predetermined value or moves away from that value. For example, in each pressure cont-act, the pressure acts on a piston balanced by a spring, and a rod transmits the movement of the piston to a spring contactor, while a mechanical stop protects the contactor against mechanical 'forces arising in the event of over pressures.

When the vehicle is in a substantially horizontal position as is shown in FIG. 2, the contactors 62 and 63 are in the top position and close the switches 65 and 67, while the switches 64 and 66 are open. The oil pressure is then the minimum normal pressure P for example 40 kg./ sq. cm. The contactor 47 is open, the pressure contact 42 being regulated so as to open it when the pressure reaches the value P and to close it if the pressure falls below that value. The contactor 48 is open, the pressure contact 43 being regulated so as to open it when the pressure is at the value P or less, and to close it when the pressure is higher. The contactor 49 is closed, the pressure contact 44 being regulated so as to open it when the pressure reaches the value P for example 50 kg./sq. cm., and to close it if the pressure is less than the value P The contactor 50 is open, the pressure contact 45 being adjusted so as to open it when the pressure is at the value P or below, and to close it when the pressure is higher. The contactor 51 is closed, the pressure contact 46 being adjusted so as to open it when the pressure reaches a value P for example 60 kg./ sq. cm., and to close it if the pressure is less. The various contactors being in the positions indicated in FIG. 2, the electrical supply circuits of the electro-magnets 56 and 61 are interrupted, and the valves 55 and 60 are closed.

The table given below indicates the various conditions of operation, the oblique strokes illustrating closure and the horizontal dashes representing opening.

The condition of operation corresponding to a value of the pressure P equal to P which is the condition illustrated in FIG. 2 of the drawings, is indicated in the second line of this table, and from a consideration of which it can be seen that the valves 55 and are closed.

If, for any reason whatever, the oil pressure falls in the jacks 14, the contactor 47 will close, thereby energizing the electro-magnet 56 and opening the valve 55. The supply of oil for the jacks will then come from the pressure source 58, 59. This condition of the control 15 in which P P is shown in the first line of the table. The oil thus supplied to the jacks will cause the supply pressure of the jacks 14 to rise. When this pressure has again reached the value P the contactor 47 opens and the electro-valve 55 re-closes thus bringing the system back to the condition shown in the second line of the table in PIP1.

If the vehicle becomes inclined in a direction which causes the liquid level N to rise in the arm 28 of the tube 23, the lever 68 is caused to pivot to move the con tactor 62 down into engagement with the switch 64. This will cause the supply circuit of the electro-magnet 56 to be closed, thereby opening valve 55 and causing the oil pressure to rise. The contactor 47 will remain open, the pressure contact 42, being in the abutment position to limit the effect of the increased forces. The contactor 48 closes as the pressure now exceeds P but the contactor 62 having moved to the bottom position, the supply circuit to the electro-magnet 61 of valve 66 remains cutoff. This is the condition indicated in the third line of the table where P P P However, when the pressure reaches P the pressure contact 44 will open the contactor 49, thereby cutting otf the supply of electricity to the electro-magnet 56. This closes valve 55 thus preventing the arrival of oil under pressure. The parts will then be in the condition indicated in the fourth line of the table, in which P=P The above described succession of automatic operations take place when as a result of the inclination of the vehicle the pressure of oil in the jacks varies from P to P Should the inclination of the vehicle become greater, the lever 69 will be caused to pivot as a result of the rise of the level N in the tube 28. This pivotal movement of lever 69 acts through the intermediary of the contactors 63, 56 and 51 to initiate a series of operations identical with those previously caused by the pivotal movement of the lever 68 and having the effect of varying the oil pressure in the jacks from P to P During this build up of the pressure the parts will be initially in the conditions indicated in the fifth line of the table, in which P P P and then will be in the conditions indicated in the sixth line of the table in which P=P If on the other hand, after having pivotally actuated the lever 68, the inclination of the vehicle is reduced, this lever will rock in the opposite direction and the contactor 62 will also go back to its initial top position. The contactor 48 being closed, the electro-magnet 61 is energized to open the valve 60. Oil is evacuated and the pressure in the jacks fall. The contactor 49 resumes its initial closed position, ready for another action if necessary. When the pressure has returned to P the contactor 48 opens, cutting-01f the supply circuit of the electro-magnet 61 and thereby causing the valve 60 to re-close. The whole of the device will then be again in the condition corresponding to a substantially horizontal position of the vehicle.

The same procedure would be followed starting from the position of maximum inclination of the vehicle, corresponding to the pressure of P to bring this pressure back to P by the action of the contactors 63, 51 and 50.

The arrangement which has been above described applies more pressure to the bottom pressure rollers 13 as the slope of the cable 10 increases. A similar arrangement comprising the means 26 and 27 can be utilized in cooperation with the other branch 29 of the tube 23, as

shown in FIG. 1 of the drawings, to provide the pressure rollers 13 in the top group with correspondingly less pressure as the inclination becomes greater. Thus, according to the invention, the bottom pressure rollers are given more pressure than the top pressure rollers, and more particularly the bottom pressure rollers are given a pressure which increases with respect to that of the top pressure rollers as the inclination increases. With such applications of pressures to the bottom and top pressure rollers there will be obtained under all circumstances of operation excellent conditions of adhesion for the driving carrier rollers 12, since the adhesion of the bottom driving rollers 12 will be increased, where the distribution of the weight of the vehicle is the least, as compared with the adhesion of the top driving rollers 12 at which the distribution of the weight of the vehicle is much heavier. For this reason, the adhesion of the bottom rollers is always adequate and the adhesion of the top rollers is never excessive.

It is also contemplated by the invention to utilize the above described arrangement in connection with the bottom rollers only and to provide the top pressure rollers with a constant pressure, which in effect amounts to the same thing as giving more pressure to the bottom pressure rollers than to the top pressure rollers, and more particularly as giving the bottom pressure rollers a pressure Which increases with respect to the top pressure rollers as the slope increases as has been described. An arrangement constructed along these indicated lines is shown in FIG. 3. In the embodiment of FIG. 3, the U-tube 23 is mounted on a double arm 75 to which is coupled at pivot 76 the upper end of a bracket 77 attached at its lower end to and supporting the vehicle 11'. The double arm 75 carries at its ends 75', 75" two trolleys 78, 78', respectively, which are pivotally mounted on such ends to rotate about the pivots 79, 79', respectively. The trolley 78 is provided with two pairs of carrier driving rollers 12 and two pressure rollers 13, 13' and the trolley 78 is provided with two pairs of carrier driving rollers 12' and two pressure rollers 13" and 13". The double arm 75 is disposed at the inclination of the cable and the U-tube 23 is mounted thereon so that the central portion thereof will also be disposed at the inclination of the cable. Only the arm 28 of the U-tube is equipped with slope-detecting and measuring means 21, 22 which are associated with the bottom pressure rollers 13, 13 on the bottom trolley 78, through the pressure regulator in the vehicle 11' and the jack 14 and accumulator 16. The jack 14 is connected to both pressure rollers 13, 13' so as to exert simultaneously the same pressure on both of these rollers. The rollers 13" and 13 of the top trolley 78 are associated with a pressure regulator 15 located in the vehicle 11' and constructed in a manner known to the art to provide a constant fixed adjustable pressure to the pack 14 and accumulator 16' on the top trolley 78'. The jack 14 is connected to both pressure rollers 13", 13 so as to exert simultaneously the same pressure on both of these rollers. The slope detecting and measuring means 21, 22, the jacks 14, 14' and the accumulators 16, 16' and the pressure regulator 15 are constructed substantially similarly to the previously described parts 21, 22, 14, 16 and 15, respectively, and cooperate in a manner similar to that described with respect to the latter in connection with the showing of FIG. 2 of the drawings. It will thus be seen that in the construction of FIG. 3, the two pressure rollers 13, 13' on the bottom trolley 78 will be provided with more pressure as the slope increases while the two pressure rollers 13", 13" of the top trolley 78' are maintained at a constant fixed predetermined pressure.

In the embodiment shown in FIG. 4 of the drawings, only the arm 29 of the U-tube 23 is equipped with slope detecting and measuring means 21, 22, and such means are associated with the pressure-rollers 13", 13 in the top trolley 78', through the jack 14' on such trolley, to provide such rollers 13" and 13" with a lower pressure as the slope of the cable 10 becomes greater. In the construction of FIG. 4, the pressure rollers 13, 13 of the bottom trolley 78 may be connected to a pressure device 15 in the manner shown in FIG. 3, or the mountings for such pressure-rollers 13 and 13 may be constructed to apply a constant fixed predetermined pressure to such rollers. In this construction also, the bottom, pressurerollers 13, 13' in accordance with the invention, will have more pressure applied thereto than is applied to the top pressure-rollers and, more particularly, the bottom pressure-rollers will be provided with a pressure which inceases as compared with that applied to the top pressurerollers, as the slope increases. Taking into account the preponderant distribution of the weight of the vehicle 11' on the rollers of the top trolley 78', the construction should be such that it is in any case ensured that there should not be applied to the top pressure rollers 13", 13" an excessive pressure such as would cause rapid wear of the rollers from excessive adhesion. As regards the constant pressure applied to the bottom rollers 13, 13 this is chosen so as to be sufiicient for the various conditions of slope.

While I have hereinabove described and illustrated in the drawings by way of example several methods by which the invention may be practiced, it will be apparent to those skilled in the art that other embodiments may be employed and that in such other embodiments manual and/ or automatic pressure-regulating means may be provided to take account of the various conditions of operation, such as when the cable is dry or covered with frost, or the vehicle lightly or heavily loaded, etc. Hence, I do not wish to limit myself to the examples disclosed, but intend to include all embodiments of the invention coming within the scope of the appended claims.

What is claimed is:

1. A self-propelled vehicle for a telpher railway comprising carrier rollers for suspending the vehicle from a cable and some of which at least are driving rollers for propelling the vehicle along the cable, pressure rollers cooperative with said carrier rollers and arranged to apply on the underside of the cable forces defining the conditions of adherence of the driving rollers which are suitable to the inclinations of the cable, certain at least of said pressure rollers having each connected thereto a hydraulic jack for pushing its connected pressure roller toward the cable, hydraulic means for supplying fluid under pressure to each jack and including regulating means constructed and arranged to select from a predetermined range of fluid pressure levels, a level of pressure capable of causing a jack to push its connected pressure roller against the cable with the force required to define the condition of adherence for the driving roller associated therewith that is suitable to the inclination of the cable, and an accumulator of the oleo-pneumatic type connected to such jack to maintain each selected level of pressure in the jack irrespective of the position of the pressure roller connected thereto with respect to the cable.

2. A self-propelled vehicle as defined in claim 1, in which all of said carrier rollers are driving rollers, and including a motor, and differential mechanisms drivingly connecting said motor to said driving rollers.

3. A self-propelled vehicle as defined in claim 1, in which each pressure roller is arranged between two adjacent carrier rollers.

4. A self-propelled vehicle as defined in claim 1, in which each accumulator of the oleo-pneumatic type is located in the immediate proximity of a jack connected to a pressure roller.

5. A self-propelled vehicle as defined in claim 1, in which said pressure rollers are arranged so as to be located at different levels when the cable is inclined, and in which said jacks and said regulating means are arranged to apply pressure to said pressure rollers so that at least one pressure roller at a lower level than at least 0116 pre sure roller at a "higher level is provided with more pressure than the latter, and in which said hydraulic means further includes slope-detection means controlling said regulating means in accordance with the slope of said cable.

6. A self-propelled vehicle as defined in claim 1, in which said hydraulic means further includes slope-detection means controlling said regulating means and operative to cause the latter to provide the jack with different fluid pressures depending on differences in the slope of the cable.

7. A self-propelled vehicle as defined in claim 6, in which said slope detection means includes means for measuring the slope and operable to cause said regulating means automatically .to increase the fiuid pressure in the jack when the slope of the cable increases.

8. A self-propelled vehicle as defined in claim 6, in which said slope detection means comprises a U-tube partially filled with liquid and having a substantially straight, elongated central portion and upstanding end arms, said U-tube being mounted on the vehicle with the central portion thereof disposed in substantial parallelism with the cable and so that the levels of the liquid in said arms thereof vary with variations in the slope of said cable, at least one submersible body located in one of said U-tube end arms, so as to cooperate with the liquid in said arm, and means connecting said submersible body to said regulating means and operable to cause the latter to vary the liquid pressures in the jack with variations in the slope of the cable.

9. A self-propelled vehicle as defined in claim 8, including a second submersible body located in one of said U-tube end arms in cooperative relation with the liquid in said arm, and second connecting means connecting said second submersible body to said regulating means and operable to cause the latter to vary the liquid pressures in a second jack with variations in the slope of the cable, said second connecting means and regulating means being constructed and arranged to apply different pressures to said second jack than is applied to the jack associated with the first mentioned submersible body and connecting means for the same slope of the cable.

10. A self-propelled vehicle as defined in claim 8, in which said regulating means is constructed and arranged with relation to said submersible body and said connecting means to apply increased pressure to an associated jack when said submersible body indicates an increase in the slope of the cable.

11. A self-propelled vehicle as defined in claim 8, in

it) which said regulating means is constructed and arranged with relation to said submersible body and said connecting means to decrease the fluid pressure in an associated jack when said submersible body indicates an increase in the slope of the cable.

12. A self-propelled vehicle as defined in claim 8, including a second submersible body located in the same arm of said U-tube end arm and at a different level in said arm than said first mentioned submersible body, and second connecting means connecting said second submersible body to said regulating means and operable to cause the latter to vary the liquid pressures in a different portion of said predetermined range of fluid pressure levels than said first mentioned submersible body.

13. A self-propelled vehicle as defined in claim 6, in which said slope detection means comprises a U-tube partially filled with liquid and having a substantially straight, elongated central portion and upstanding end arms, said U-tube being mounted on the vehicle with the central portion thereof disposed in substantial parallelism with the cable and so that the levels of the liquid in said arms thereof vary with variations in the slope of said cable, and control means connected to one of said U- tube end arms and to said regulating means, said control means cooperating with and controlled by the liquid in said arm to control said regulating means and operable to cause .the latter to vary the liquid pressures in the jack with variations in the slope of the cable.

14. A self-propelled vehicle as defined in claim 1, including means connected to each of other pressure rollers and independent of said jacks and hydraulic means, said connected means being constructed and arranged to apply to said other pressure rollers given pressures different from the pressures applied by said jacks to the pressure rollers associated therewith.

References Cited by the Examiner UNITED STATES PATENTS 1,336,562 4/1920 Hellmund 31852 1,986,413 1/1935 Ruemelin -153 2,162,688 6/1939 Lawrence 105--l53 2,228,034 1/1941 Nelles 10530 2,286,680 6/1942 Hines 291-2 ARTHUR L. LA POINT, Primary Examiner.

B. FAUST, Assistant Examiner. 

1. A SELF-PROPELLED VEHICLE FOR A TELPHER RAILWAY COMPRISING CARRIER ROLLERS FOR SUSPENDING THE VEHICLE FROM A CABLE AND SOME OF WHICH AT LEAST ARE DRIVING ROLLERS FOR PROPELLING THE VEHICLE ALONG THE CABLE, PRESSURE ROLLERS COOPERATIVE WITH SAID CARRIER ROLLERS AND ARRANGED TO APPLY ON THE UNDERSIDE OF THE CABLE FORCES DEFINING THE CONDITIONS OF ADHERENCE OF THE DRIVING ROLLERS WHICH ARE SUITABLE TO THE INCLINATION OF THE CABLE, CERTAIN AT LEAST OF SAID PRESSURE ROLLERS HAVING EACH CONNECTED THERETO A HYDRAULIC JACK FOR PUSHING ITS CONNECTED PRESSURE ROLLER TOWARD THE CABLE, HYDRAULIC MEAND FOR SUPPLYING FLUID UNDER PRESSURE TO EACH JACK AND INCLUDING REGULATING MEANS CONSTRUCTED AND ARRANGED TO SELECT FROM A PREDETERMINED 